Hyperthymesia and Memory Distortion

How do we remember information? How memory works is often analogized to a computer’s information-processing system. To remember any event, we must get the information into our brain through the process of encoding, or the processing of information into the memory system, retain the information over time through storage, and later get it back out, through retrieval. A computer also encodes, stores, and retrieves information. First, it translates input (keystrokes) into an electronic language, much as the brain encodes sensory information into a neural language. The computer permanently stores vast amounts of information on a drive, from which it can later be retrieved.

But, imagine being able to recall every moment of your entire life, beginning around age 10. UC Irvine neuroscientists James McGaugh and Larry Cahill studied people with this type of phenomenal memory, hyperthymesia. Their first scientific paper in 2006 consisted of a study about a woman nicknamed AJ (Jill Price), who had hyperthymesia. Hyperthymesia, also known as highly superior autobiographical memory (HSAM), is a condition in which one can remember astonishing details about every single day of their life going back to childhood. Given any specific date in the last few decades, Brad Williams can remember both what he did that day and what significant world events occurred. Bob Petrella can recall the date he met every one of his friends and associates. Jill Price can remember the day that any episode of any TV show she’s ever seen first aired—including, in a handful of cases, that day’s weather.

“Researchers have previously found that memories can be distorted in every group they’ve looked at: in the young, the old, those with high intelligence and those with low intelligence,” Lawrence Patihis, a psychologist at UC Irvine and the lead author of the new study, says. “And when we looked at people with HSAM, in all measures, we found memory distortions too.”

To test whether these people could be deceived into remembering false or distorted memories, the researchers enlisted 20 people with hyperthymesia and compared their performance in a set of standard memory implantation tests—which attempt to fool the participant into recalling incorrect specifics or events that didn’t occur—to 38 people with normal memory. These types of tests have frequently been used in the push for limiting the reliance on witness testimony in the criminal justice system, as they indicate that people often misremember events and details because of leading questions.

In the first test, the participants were shown a series of 15 related words one by one on a screen. Then, afterward, they were tested on whether they’d seen specific words, including a critical “lure” word that was related to the rest but did not actually appear. Most non-hyperthymestic people taking the test would report seeing the lure word even though it was never displayed, because they’d associate it with the words actually shown.

But what about hyperthymestic people? In the experiment, both the control group and the participants with hyperthymesia said they observed the "lure" 70 percent of the time.

The second test involved a slideshow of photographs that portrayed a crime. Forty minutes later, the participants read a text narrative that described the same event, but also included six detailed errors. After this, the participants were given multiple choice questions on what they saw in the original photos. Both groups made errors, influenced by the text they read after seeing the photos. However, the people with hyperthymesia made nearly 73 percent more errors than the control group, perhaps indicating a greater reliance on textual cues.

The results of the third test were the most staggering. Dispersed among dozens of irrelevant facts about recent history that were meant to distract, the participants were told that, on 9/11, someone had captured footage of United Flight 93 crashing in Pennsylvania. Then, on a written questionnaire, they were asked if they’d seen that “well-publicized footage.” Twenty-nine percent of the control group and twenty percent of the hyperthymestic participants reported that they’d seen the footage—an impossibility, because no such video exists.

Anyways, the study served as a broader glimpse into the memory processes of people with hyperthymesia and how they might—or might not—actually differ from the rest of the human race.

One of this study’s authors, Aurora LePort, had previously conducted neurological research into the same people with HSAM tested in this study, and found structural differences in their brains, including stronger white matter in areas specifically associated with autobiographical memory—recall of events that occurred to oneself—rather than areas linked to wider applications of memory. The reality that these people can’t perform any better on memory distortion tests similarly implies a fundamental difference between autobiographical memory (at which they clearly surpass the average human in) and memory as a whole.

For your reading pleasure, here's the article: http://blogs.smithsonianmag.com/science/2013/11/even-people-with-perfect-memory-can-be-tricked-into-recalling-fake-events/